Method of die rolling



Patented Nov. 16, 1926.

UNITED STATES WILLIAM P. WITHEROW, F PITTSBURGH, PENNSYLVANIA, ASSIGNOB 'IO WITHEBOVP 1,607,498 PATENT OFFICE.

STEEL COMPANY, OF NEVILLE ISLAND, PENNSYLVANIA, A CORPORATION 01 PENN- SYLVANIA.

No Drawing.

This invention relates to die rolling, and

'is particularly valuable for producing dierolled articles in large quantities.

. One of the most expensive items of the 6 commercial operation of a die-rolling estab:

lishment is the initial setting of the rolls in Y the mill and the adjustment thereof to secure the desired results. These operations require a very large amount of time before any 10 commercial product can be secured from the mill. The adjustments required in commercial die rolling are far more delicate than those in ordinary rolling practice, for it will be appreciated that the upper and lower rolls must be adjusted relatlve to one another, the temperature conditions must be accurately secured and maintained, and a number of other factors enter in, so that when the initial setting is once secured and commercial articles are produced, it is highly desirable to maintain such setting and keep the mill running as long as possible so as to secure maximum tonnage.

The limiting factor heretofore has been the fact that the roll grooves soon become roughened to such an extent that the surface of the article is materially affected, and in fact, the dimensions of the article are frequently changed by this roughening of the roll matrix patterns. This roughening is most apparent in those portions of the article where the greatest reduction'from the leader is accom lished or where the section is very narrow. e side portions of the roll 36 grooves soon become roughened and they seem to grip the hot leader in such manner that it can not flow smoothly into the groove and fill out. Consequently, the articles produced are not upto dimension and they pre- 40 sent a ver rough surface.

Hereto ore when this condition has obtained, it has been necessary to shut down the mill and'change rolls, thus materially increasing the expense. I rovide for olish- I ing matrix portions of t e rolls whi e they are in the mill and have found that after such polishing the run may be continued. In actual practice, it has been found that a pair of rolls which were effective for producing commercial articles for onl two or three hours might, by polishing in p ace, at two or three hour intervals, be used oreight or ten \hours without material reduction in the quality of the die-rolled product. The pol- Applieatlon filed 'July 18,

1925. Serial n. 44,111.

ishing operation is carried outwith portable grinders or polishers and may be accomplished within a very short space of time. In fact, the rolls are still quite hot when the second stage of the run is commenced and little or no further adjustment of the mill is required.

The side portions of the roll matrix, particularly in those portions where heavy reductions occur, will be found to be the roughest, and the will cause the corresponding portions of t e article to present a very roughened and cracked appearance. Furthermore, those portions of the article are not up to dimension, as the free flow of the metal in the matrix is apparently interfered with by the rough Walls and uncommercial articles are accordingly produced. When this condition is observed in the rolled prodnot, the mill is stopped and one or two workmen immediately start to polish the matrix portions of the rolls. The work may very readily be carried out by having one man on one side of the mill work on the u per roll and another man on the other si e of the mill work on the lower roll. Portable grinders or polishers have been used with great succem, and the work of polishing a groove may be carried out in a veryv few minutes.

The dimensions of the matrix are not materially altered by the polishing operation, and it may be repeated anumber of times without such changes in dimensions as will cause the production of articles outside the dimensional tolerances usually given.

By my invention, the time required for changing rolls and adjusting the mill need be spent only at the beginnin of a run and the polishing operation may carried out from time to time as r uired, in order to keep' the articles up to t e required standards. The expense of roll-ing is materially reduced b this step, and a far greater ro-. portion 0 the mill time maybe devo to actual production rather than to the time; consuming stepsnecessary in the preparation of the run.

While I have described the preferred manmi of carrying out the invention, it will be understoodthat it is not so limited, as it may be otherwise practiced within the scope of. the following claims.

I claim:

1. The method of die rolling, which ill-- eludes passing leaders between die rolls having matrix portions which vary'in cross-secof the rolls, and then utilizi the re s for a the further production of sue articles.

2. In the method-of die'rolling, the steps consisting in passing leaders between normally rotating die rolls having matrix portions which vary in crossssectional size or shape to produce a plurality of articles which are of different cross-sectional size or shape at diiferent points, continuing the operation until the rolls have become roughened at the matrix portions thereof.

stopping the rotation of the rolls and polishing the roughened portions of the rolls by guiding a polishing tool over such roughened portions while the rolls are inoperative.

3. In the method of die rolling, .the steps consistingin passing leaders between nor mally rotating-die rolls having matrix portions which vary in cross-sectional size or shape to produce a plurality of articles which" are of diflerent cross sectional size or sha at different points, continuing the operatlon until the rolls have become roughened the matrix portions thereof, stoppingthe rotation of the rolls and polishing the roughened portions of the rolls by guidtool over such roughened ing a. polishin iavin other portions on the portions while peripheral surface 0 the rolls unpolished,

said polishing step being carried out while,

the rgllslare ino erative.

the met 0d of die rolling, the steps consisting in passing leaders between normally rotating die rolls having matrix portions which vary in cross-sectional size or shape to produce a plurality of articles which are of difierent cross-sectional size.

or shape at different points, continuing the operation until the rolls have become roughened at the matrix portions thereof, stopping the rotation of the rolls and polishing those matrix portions where the greatest reduction is eifected by guiding apolishing tool over such portions while the rollsare inoperative.

In testimony whereof I have h ereunto set my hand. v

WILLIAM P. WITHEROW. 

